Influência da via hippo no reparo da mucosite oral quimicamente induzida em modelo murino submetida a tratamento com laser, geleia real ou própolis / Influence of the hippo pathway on the repair of chemically induced oral mucositis in a murine model subjected to treatment with laser, royal jelly or propolis

A via hippo é uma via de transdução de sinal altamente conservada que está implicada no desenvolvimento, homeostase e regeneração celular/tecidual. A YAP tem papel fundamental na via hippo uma vez que junto com a TAZ ativam fatores de transcrição que levam ao crescimento, diferenciação e migração celular. O mecanismo de fosforilação da YAP/TAZ pela LATS1/LATS2 cria um sítio de ligação para manter a YAP no citoplasma (fosforilada) impedindo suas funções a nível nuclear. Diante das importantes funções desta via no reparo e crescimento tecidual, esta pesquisa avaliou se a via hippo exerceu influência na resposta ao tratamento da MO através da expressão das proteínas YAP e LATS2 em mucosite oral (MO) quimicamente induzida pelo 5- fluoracil (5-FU), em modelo murino, tratada com própolis (P), geleia real (GR) ou laser (L) comparadas ao grupo controle (C), sem tratamento. Foram utilizadas amostras de ratos machos wistar divididos nos seguintes grupos: C, P, GR e L (intraoral 6 J/cm2 ) separados em três tempos experimentais: dias 08, 10 e 14. O perfil de imunomarcação foi feito por escores padronizados entre 0 a 3 levando em consideração a marcação nuclear e/ou citoplasmática. Na análise de imunomarcação da YAP, no dia 08, o grupo controle obteve os escore 0 e 1 na maioria das amostras, já nos dias 10 e 14 a maior parte das amostras obteve os escore 2 e 3. Nos grupos experimentais (L, GR e P), o escore 2 prevaleceu em todos os tempos experimentais. Para LATS2 houve prevalência do escore 2 tanto no grupo controle quanto nos grupos teste em todos os tempos experimentais. Em relação a análise estatística da imunoexpressão da proteína YAP, verificou-se diferença estatítica significativa (p= 0,020), apenas no dia 08 entre o grupo controle comparado aos grupos experimentais (L, GR e P). Já para LATS2 nenhuma diferença estatística foi encontrada. Na avaliação estatística dos diferentes tempos experimentais dentro um mesmo grupo, só foi encontrada diferença estatística significativa no grupo laser e apenas para LATS2 (p=0,025). Adicionalmente foi realizada a correlação de spearman, entre YAP e LATS2 para todos os grupos, porém não houve associação estatística significativa. A maior imunoexpressão de YAP e LATS2 (escores 2 e 3) observada nos grupos experimentais, indica que a via hippo é ativada e parece influenciar o processo de reparo nas mucosites orais quimioinduzidas e tratadas pelos diferentes métodos (AU).

The hippo pathway is a highly conserved signal transduction pathway that is implicated in cell/tissue development, homeostasis and regeneration. YAP plays a key role in the hippo pathway since, together with TAZ, they activate transcription factors that lead to cell growth, differentiation and migration. The YAP/TAZ phosphorylation mechanism by LATS1/LATS2 creates a binding site to keep YAP in the cytoplasm (phosphorylated) preventing its functions at the nuclear level. Given the important functions of this pathway in tissue repair and growth, this research evaluated whether the hippo pathway exerted influence on the response to OM treatment through the expression of YAP and LATS2 proteins in oral mucositis (OM) chemically induced by 5-fluororacil (5- FU), in a murine model, treated with propolis (P), royal jelly (GR) or laser (L) compared to the control group (C), without treatment. Samples of male Wistar rats divided into the following groups were used: C, P, GR and L (intraoral 6 J/cm2) separated into three experimental times: days 08, 10 and 14. The immunostaining profile was performed by standardized scores between 0 to 3 taking into account nuclear and/or cytoplasmic labeling. In the YAP immunostaining analysis, on day 08, the control group obtained scores 0 and 1 in most samples, while on days 10 and 14 most samples obtained scores 2 and 3. In the experimental groups (L, GR and P), score 2 prevailed at all experimental times. For LATS2 there was a prevalence of score 2 both in the control group and in the test groups at all experimental times, showing a very heterogeneous expression. Regarding the statistical analysis of YAP protein immunoexpression, there was a statistically significant difference (p= 0.020), only on day 08 between the control group compared to the experimental groups (L, GR and P). As for LATS2, no statistical difference was found. In the statistical evaluation of the different experimental times within the same group, a statistically significant difference was only found in the laser group and only for LATS2 (p=0.025). Additionally, the Spearman correlation was performed between YAP and LATS2 for all groups, but there was no statistically significant association. The greater immunoexpression of YAP and LATS2 (scores 2 and 3) observed in the experimental groups indicates that the hippo pathway is activated and seems to influence the repair process in chemoinduced oral mucositis treated by different methods (AU).

Role of the route of leukotrienes in an experimental model of oral mucositis induced by 5-fluorouracil

Abstract Purpose: To investigate the participation of cysteinyl leukotrienes in the pathophysiology of oral mucositis. Methods: Oral mucositis was induced in hamsters using 5-fluorouracil (5-FU; 60 and 40 mg/kg; i.p., on days 1 and 2, respectively, and with excoriations in jugal mucosa on day 4). Montelukast (10, 20, or 40 mg/kg/d; gavage), MK886 (3 mg/kg/d, i.p.), or saline or celecoxib (7.5 mg/kg/d; i.p.) was administered 1 h prior to 5-FU and daily, until the fourth (MK886) or tenth day, when the animals were euthanized and their jugal mucosa was collected for macroscopic, histopathological, and immunohistochemical evaluation. Results: Neither montelukast nor MK-886 prevented the oral mucositis induced by 5-FU, as observed by histopathological evaluation. In addition, we did not find significant differences in the expression of inducible nitric oxide synthase-2, cyclooxygenase-2, or interleukin (IL)-1β between the experimental and control groups. However, we did observe a significant decrease in tumor necrosis factor (TNF)-α expression for all doses of montelukast; we also observed a significant decrease in IL-10 with 40 mg/kg/d and MK 886. Conclusions: Cysteinyl leukotrienes do not play an important role in experimental oral mucositis induced by 5-FU. There is a modulating action specifically on TNF-α.